Google is introducing some improvements on the way it gives Ad units a corresponding Quality Score. This improvements are follow-ups to the most recent changes that Adwords has introduced such as the guidelines on slow loading
Ad Landing Pages.
These improvements specifically relates to calculation of
Quality Score at the time of each search query, phasing out marking keywords with “inactive for search” and the replacement of “minimum bid” with “first page bid.”
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Google Adwords Quality Score Gets a Revamp 
